My friends range from socialists to near-anarchists. It was one of the latter, in Philadelphia this past weekend, who defined his jaundiced view of government operations thus: "Let us tell you the best way for you to spend your money; in fact, we'll even do it for you. And remember, next year we will change our minds about what is best."

Today I want to talk about a scientific effort that was not a government program; then, for a brief period, it was a government program; and now it is again not a government program. It is known as SETI, which stands for the Search for Extraterrestrial Intelligence, and over the years it has had the misfortune to become entangled by the media with other decidedly non-scientific efforts.

I hate even to mention some of these, because it publicizes them. However, SETI has nothing to do with the "face on Mars," which later pictures from space proved was a natural feature of the Mars landscape; nor has it anything to do with the "Roswell incident," in which a classified weather balloon experiment escalated to the arrival of aliens on Earth and their subsequent concealment by the United States Government; and SETI certainly has nothing to do with astrology, in which individual fortunes are divined from stellar and planetary positions. (No, I don't believe in astrology at all, but I can't stop my wife reading me my horoscope from the morning paper.)

I talked some in an earlier column about SETI, the search for signals from space, and mentioned that anyone can become personally involved. I didn't quite say how, and reader response suggests that this caused some confusion. Today I want to remedy that by giving more details.

Let's begin with the confusing part. There are in fact two different SETI projects. They share a common aim: the discovery of a signal that will prove, beyond a doubt, that we are not the only intelligent species in the universe. Both programs believe that the way to conduct the search is to look for signals in a particular region of radio frequencies, known in the communications business as C-band. Both programs are short of money.

Why, then, are there two efforts? A government-funded program often benefits by encouraging competition between groups, but here it sounds as though it would make more sense to pool resources.

History has a lot to do with it. For a brief period in the early 1990's, the U. S. government funded a SETI group attached to NASA Ames. The amount was a few million dollars a year. That's a lot to you and me, but a minuscule fraction of what we spend on defense or health or social programs.

Small or large, the amount made little difference, because just one year after approving the program, the government canceled it. At that point the whole thing was supposed to shrivel up and die. However, workers on SETI had been there before. A small SETI program was government-funded, then strangled, in the early 1980s. This time the SETI enthusiasts were rather better prepared. They scrambled for private support and were able to continue as the SETI Institute.

That sounds like a happy ending, but there is a catch. The SETI Institute is in effect continuing the program laid out when it was funded by the government. Certain nearby stars were selected as the "best bets" for places where life, and intelligent life, may have developed. Large radio telescopes were to listen hard for signals from those target stars. There is sufficient funding - just - to keep such a program going at the SETI Institute, in cooperation with several other groups around the world.

Now for the catch. Suppose that there is intelligent life out there, but its home is much farther away than the nearest stars. Radio signals can be detected from incredible distances - we have used one of our own radio telescopes, at Arecibo in Puerto Rico, to send a coded message that could be heard 25,000 light-years away with detection equipment no better than what we have ourselves. If someone that far away is sending a signal in our direction, it will not be associated with some bright star, possibly not even with any star that we know.

This suggests that we need to supplement the "target star" approach with a different one - an "all-sky" survey which makes no prior assumptions about the direction of origin of the signal. Such an all-sky search needs not just a few radio telescopes, but hundreds or thousands of them. The organization working to provide the necessary numbers is the SETI League. Its "Project Argus" is funded totally by private citizens. Its aim is to make it possible for thousands of interested amateurs to take part in the collection and analysis of potential SETI signals.

And how, you may ask, could an average citizen possibly obtain a radio telescope dish suitable for this work, without handing over a few tens or hundreds of thousands of dollars? Simple. The countryside is littered with them. Whenever you see a sizable satellite dish, ten or fifteen feet across, in someone's yard, chances are that dish is no longer in use. It has probably been replaced by a far smaller dish that receives radio signals at a higher frequency. Often, the old dish is now junk and yours for the asking. And it is exactly the size and type of dish needed for SETI all-sky searches.

Of course, you need more than the satellite dish, you also need some electronics hardware, plus a personal computer (not a powerful one; any Pentium will do fine, or even an old 486 processor). Your total hardware investment should be under $1,000. Software will come to you free.

If all this sounds interesting, get in touch with the SETI League, www.setileague.org, and receive a hundred times as much information as I can possibly offer here. Or, if you want to compare the programs of the SETI League and the SETI Institute, visit also www.seti-inst.edu.

Wouldn't it be a real kick to be the first person ever to pick up that long-awaited message from deep space?

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